UT Researcher Learns Cleaning is a Big Job for Little Shrimp

“Our guys are pretty little,” she said. “For shrimp, they’re on the small end.”

The
junior’s research on Hawaiian river shrimp, a crustacean about the size
of a cashew, has netted her two research awards, the Department of
Biology’s $3,000 Summer Research Fellowship grant and a head start on
graduate school.

Since July 2008, she and Dr. Jen Wortham,
a UT exercise science and sport studies associate professor, have
studied the grooming habits of the species Macrobrachium grandimanus.
How and how often these shrimp clean themselves is a matter of life and
death. Debris flowing through the river can collect on them “like
barnacles” and lodge in their gills, Van Maurik said. Too much build-up
could paralyze or even suffocate them.

To make matters worse, development in Hawaii is destroying their habitat, causing erosion and creating more run-off.

“The more gunk added to the water, the more the shrimp need to clean,” Wortham said.

They
clean a lot, Van Maurik and Wortham’s research shows. Whereas other
species, such as mantis shrimp, devote 3 to 4 percent of the day to
grooming, the Hawaiian river variety spends about a quarter of their day
cleaning themselves. Imagine taking a six-hour shower every day.

And
these tiny creatures don’t just lather up the shower gel on their
luffa. Grooming is hard work. The shrimp scrape, scratch and pick off
dirt and debris with their front claws and back legs, even reaching
inside their mouths to clean their gills.

Van Maurik and
Wortham’s main research method is observation, including 24-hour,
bleary-eyed vigils spent in the Marine Behavioral Research Laboratory in
Walker Hall to see if the tiny creatures groom more during the day or
at night.

Hawaiian river shrimp.

“They really start moving at night,” Van Maurik said.

They’re
also trying to figure out the function of the mysterious “hair” patch
(or “setal,” as it’s known to scientists) on the inside of the shrimp’s
larger claw. They had suspected the fastidious crustacean would use it
to brush dirt off its body.

“After over 30 hours of watching this shrimp, it wasn’t used once. It’s so weird,” Wortham said.

Why
study Hawaiian river shrimp? Little is known about the species, which
is always an open invitation for researchers. The opportunity arose when
UT assistant professor of biology Dr. Mark McRae, who is a Hawaiian
conservation ecologist and is collaborating on the project, got the
shrimp from the Hawaii Division of Aquatic Resources.

Van
Maurik and Wortham will continue their research into next year. They
hope to present their findings January 2010 at The Society of
Integrative and Comparative Biology’s international conference in
Seattle.

The research awards Van Maurik won include the
Florida Academy of Sciences’ outstanding undergraduate paper in the
biological sciences and the American Association for the Advancement of
Science’s best student presentation by a female undergraduate. Van
Maurik is one of two undergraduates to receive a biology department
research fellowship.

Wortham graduated from UT in 1995 with a
marine science degree and earned a Ph.D. in evolutionary biology from
the University of Louisiana – Lafayette. Her research focuses on
crustacean behavior, especially mantis shrimp.